Pisco Formation

The Pisco Formation is a geologic formation located in Peru, on the southern coastal desert of Ica and Arequipa. The approximately 640 metres (2,100 ft) thick formation was deposited in the Pisco Basin, spanning an age from the Late Miocene up to the Early Pliocene, roughly from 9.6 to 4.5 Ma. The tuffaceous sandstones, diatomaceous siltstones, conglomerates and dolomites were deposited in a lagoonal to near-shore environment, in bays similar to other Pacific South American formations as the Bahía Inglesa and Coquimbo Formations of Chile.

Pisco Formation
Stratigraphic range: Late Miocene-Early Pliocene (Tortonian-Zanclean)[1] ~9.6–4.5 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Lithology and sediments of the Pisco Formation across its allomembers
Type	Geological formation
Unit of	Pisco Basin
Overlies	Chilcatay & Caballas Formations
Thickness	640 m (2,100 ft)
Lithology
Primary	Tuffaceous sandstone, diatomaceous siltstone
Other	Conglomerate, dolomite
Location
Coordinates	15.7°S 74.5°W / -15.7; -74.5
Approximate paleocoordinates	15.8°S 73.8°W / -15.8; -73.8
Region	Arequipa & Ica Regions
Country	Peru
Extent	From Pisco to Yauca
Type section
Named for	Pisco
Outcrops of the formation in Peru

Several specialists consider the Pisco Formation one of the most important Lagerstätten,^[2][3] based on the large amount of exceptionally preserved marine fossils, including sharks (most notably megalodon), penguins, whales, dolphins, birds, marine crocodiles and aquatic giant sloths.

Famous fossils found in these layers include the giant raptorial sperm whale Livyatan,^[4] the aquatic sloth Thalassocnus,^[5] the sperm whale Acrophyseter, and the walrus-like dolphin Odobenocetops.^[6]

Description

The Pisco Formation of the Pisco Basin consists of tuffaceous sandstones, diatomaceous yellow to gray siltstones and a basal conglomerate.^[7] The formation is deposited from Pisco in the north to Yauca in the south. The northern portion is known as the Ocucaje Area and the southern part as the Sacaco Area.^[8] The total thickness of the formation is estimated at 640 metres (2,100 ft).^[9] The formation unconformably overlies the Chilcatay and Caballas Formations.

Paleobiota of the Pisco Formation

The Pisco Formation has provided a rich resource of marine fauna, including marine mammals like cetaceans and seals, large fishes, reptiles, and penguins.^[10] It is also one of the richest sites in the world for fossil cetaceans, with close to 500 examples being found in the formation.^[11]

The oldest fossils of the aquatic sloth Thalassocnus (T. antiquus) come from the Aguada de Lomas horizon of the Pisco Formation and were dated at roughly 7 Ma. The youngest specimen (T. carolomartini) was found in the Sacaco horizon and dated to approximately 3 Ma.^[12] Thalassocnus was preyed upon by the probable apex predators of the environment, Livyatan and megalodon.^[13][14] The youngest strata belonging to the formation have been dated at 2 Ma, corresponding to the Early Pleistocene (Uquian). Fossils of the Humboldt penguin were found in these deposits at the Yauca locality.^[15]

Birds

Taxa	Species	Locality	Materials	Description	Images	Notes
Spheniscus	S. humbodti			Humboldt penguin		[15]
	S. megarhampus			Banded penguin		[15]
	S. muizoni			The oldest banded penguin		[16][17]
	S. urbinai			A larger banded penguin than S. muizoni		[15]
Ramphastosula	R. aguierrei					[18][19]
	R. ramirezi
Sula	S. brandi					[20][21]
	S. magna
	S. sulita
Morus	M. peruvianus					[20]
Perugyps	P. diazi					[20]
Ciconiidae indet.	Gen. et sp. indet.					[22]
Fulmarus	Fulmarus sp.					[18]
Pelagornis	Pelagornis sp.					[23][24]
Pelecanus	Pelecanus sp.					[25]
Phalacrocorax	P. aff. bougainvillii					[18][26]
	cf. Phalacrocorax sp.

Fish

Bony fish

Taxa	Species	Description	Images	Notes
Alosinae	A. indet	A type of herring		[10]
Centropomidae	C. aff. Psamoperca	A snook fish		[10]
Triglidae	T. indent	A type of sea robin		[10]
Xiphiidae	X. ident	A sword fish		[10]
Sardinops	S. sp.	A sardine		[27]

Rays

Taxa	Species	Description	Images	Notes
Myliobatis	Indeterminate	A species of eagle ray		[10]

Sharks

Taxa	Species	Description	Images	Notes
Carcharias	C. taurus	The sand tiger shark		[18]
Carcharhinus	C. sp. indent	A requiem shark		[10]
Carcharodon	C. carcharias	The great white shark		[28][18]
	C. hubbelli
Cosmopolitodus	C. hastalis	The broad-toothed mako		[10]
Hexanchus	H. gigas	A cow shark		[28]
Isurus	I. oxyrhincus	The shortfin mako		[23]
Otodus	O. chubutensis			[10]
	O. megalodon	The largest of the megatoothed sharks (and of all fishes)

Mammals

Cetaceans

Taxa	Species	Locality	Material	Description	Images	Notes
Acrophyseter	A. deinodon			A small raptorial physeteroid		[20][29]
	A. robustus
Atocetus	A. iquensis			A small toothed whale		[30][31]
Australithax	A. intermedia			A long-snouted porpoise		[32]
Balaenoptera	B. siberi			A baleen cetacean		[23][33]
Belonodelphis	B. peruanus			A long delphinid		[23][30][34]
Brachydelphis	B. jahuayensis			An early delphinid		[23][30][35][36]
	B. mazeasi
Brujadelphis	B. ankylorostris			A river delphinid		[37]
Hemisyntrachelus	H. oligodon			An early form of orca		[18]
Incakujira	I. anillodefuego			A small baleen cetacean		[23][38]
	I. fordycei
Kogia	K. danomurai			A basal member of the Kogia genus. Small physeteroid		[39]
Koristocetus	K. pescei			A small sperm whale		[40]
Livyatan	L. melvillei			An 18-meter long raptorial physeteroid with 36 centimetres (1.18 ft) teeth		[4]
Lomacetus	L. ginsburgi			A cetacean		[23][41]
Mamaziphius	M. reyesi			An early beaked whale.		[42]
Miocaperea	M. pulchra			A cetothere whale		[43]
Ninoziphius	N. platyrostris			A giant beaked whale		[18]
Odobenocetops	O. leptodon			A cetacean with dual tusks		[6]
	O. peruvianus
Piscobalaena	P. nana			A small baleen whale		[18][27]
Piscocetus	P. sacaco			An extinct cetacean		[28]
Piscolithax	P. aenigmaticus			A porpoise		[18][23]
Pliopontos	P. littoralis			An early delphinid		[18]
Scaphokogia	S. cochlearis			An extinct pygmy sperm whale		[23][44]

Pinnipeds

Seals

Taxa	Species	Locality	Material	Description	Images	Notes
Acrophoca	A. longirostirus			A large pinniped thought to be the ancestor of the leopard seal		[18]
Australophoca	A. changorum			A phocidae seal.		[23]
Hadrokirus	H. martini			A species of true seal		[18][45]
Hydrarctos	H. lomasiensis			An Otariidae seal.		[18]
Magophoca	M. brevirostris			A monachinae seal.		[46]
Piscophoca	P. pacifica			A phocidae seal		[27]

Xenarthrans

Sloths

Taxa	Species	Locality	Materials	Description	Images	Notes
Thalassocnus	T. antiquus			a semi-aquatic marine sloth		[5][18] [20][28]
	T. carolomartini
	T. littoralis
	T. natans

Mollusks

Bivalves

Taxa	Species	Description	Images	Notes
Dosinia	Indeterminate			[18]

Polychaetes

Taxa	Species	Description	Images	Notes
Diplochaetetes	D. mexicanus			[47]

Gastropods

Taxa	Species	Description	Images	Notes
Acanthina	A. obesa			[18]
	A. triangularis			[18]
Concholepas	C. kieneri			[18]
Herminespina	Indeterminate			[18]

Reptiles

Taxa	Species	Description	Images	Notes
Sacacosuchus	S. cordovai	A gavialid crocodylian		[48]
Piscogavialis	P. jugaliperforatus	A gryposuchine gavialid crocodylian		[20][27]
Pacifichelys	P. urbinai	A sea turtle		[13][49]
Chelonia	Indeterminate			[10]
Eusuchia	Indeterminate			[18]

Correlations

Laventan

Laventan correlations in South America

Formation	Honda	Honda	Aisol	Cura-Mallín	Pisco	Ipururo	Pebas	Capadare	Urumaco	Inés	Paraná	Map
Basin	VSM	Honda	San Rafael	Caldera	Pisco	Ucayali	Amazon	Falcón		Venezuela	Paraná	Pisco Formation (South America)
Country	Colombia	Bolivia	Argentina	Chile	Peru			Venezuela			Argentina
Boreostemma
Hapalops
Miocochilius
Theosodon
Xenastrapotherium
Mylodontidae
Sparassodonta
Primates
Rodents
Birds
Terror birds
Reptiles
megalodon
Flora
Insects
Environments	Fluvial			Fluvio-deltaic		Fluvio-lacustrine		Fluvio-deltaic			Fluvial	Laventan volcanoclastics Laventan fauna Laventan flora
Volcanic	Yes

See also

• Bahía Inglesa Formation, contemporaneous fossiliferous formation of Chile
• Castilletes Formation, contemporaneous fossiliferous formation of the Cocinetas Basin, Colombia
• Cerro Ballena, contemporaneous fossil site of the Bahía Inglesa Formation of Chile
• Coquimbo Formation, contemporaneous fossiliferous formation of Chile
• Collón Curá Formation, contemporaneous fossiliferous formation of Patagonia, Argentina
• Honda Group, contemporaneous fossiliferous formation of Colombia
• Navidad Formation, contemporaneous fossiliferous formation of Chile
• Pebas Formation, contemporaneous fossiliferous formation of the Amazon Basin
• Urumaco, contemporaneous fossil site of the Falcón Basin, Venezuela